Abstract:

A device is provided for the emergency operation of at least one closure
element of a cooling air supply apparatus and a correspondingly
implemented cooling air supply apparatus for an internal combustion
engine of a motor vehicle, a closure element being mechanically
operationally linked to an actuator. The closure element is situated so
it is movable between a closed position, in which it essentially closes a
ventilation opening, and an open position, in which it releases the
ventilation opening for cooling air to flow through. The actuator
automatically transfers the closure element into the open position if a
predetermined temperature is exceeded.

Claims:

1. A device for emergency operation of a closure element of a cooling air
supply apparatus for an internal combustion engine of a motor vehicle,
comprising:an actuator that is mechanically operationally linked to the
closure element; anda ventilation opening that is essentially closed by
the closure element when the closure element is in a closed position and
cooling air flows through the ventilation opening when the closure
element is in an open position,wherein the actuator is adapted to
automatically transfer the closure element into the open position if a
predetermined temperature is exceeded.

2. The device according to claim 1, wherein the actuator is a
temperature-sensitive element and subject to a change that causes
movement for the closure element as a function of an ambient temperature.

3. The device according to claim 1, wherein the actuator is coupled to a
restoring mechanism that transfers the closure element into the closed
position if there is a temperature drop below a predetermined temperature
level.

4. The device according to claim 1, wherein the closure element is
implemented as a lamella that is mounted for rotation.

5. The device according to claim 4, wherein the actuator and the lamella
are couple to using a crank that is linked and spaced apart from a
rotational axis of the lamella.

6. The device according to claim 1, wherein the actuator is implemented as
a bimetal spring.

7. The device according to claim 1, wherein the actuator has a cylindrical
receptacle for a medium that expands under an effect of heat, and a
piston adapted to move in a cylinder longitudinal axis, the medium being
implemented to at least regionally press the piston out of a receptacle
under the effect of heat.

8. The device according to claim 1, wherein the actuator is in thermal
contact with the internal combustion engine of the motor vehicle.

9. The device according to claim 1, wherein the actuator is activatable by
an electrical auxiliary drive that is powered by a power supply decoupled
from electronics of the motor vehicle.

10. A cooling air supply apparatus for an internal combustion engine of a
motor vehicle; comprising:a first operable closure element; anda second
operable closure element, the second operable closure element
comprising:an actuator that is mechanically operationally linked to the
second operable closure element; anda second ventilation opening that is
essentially closed by the second operable closure element when the second
operable closure element is in a closed position and cooling air flows
through the second ventilation opening when the second operable closure
element is in an open position,wherein the actuator is adapted to
automatically transfer the second operable closure element into the open
position if a predetermined temperature is exceeded.

11. The cooling air supply apparatus according to claim 10, wherein the
first operable closure element and the second operable closure element
are coupled to a common actuating drive that is adapted to alternate
opening and closing of a first ventilation opening and the second
ventilation opening.

12. The cooling air supply apparatus according to claims 10, wherein the
first operable closure element is operationally linked for emergency
operation and decoupled from the first operable closure element.

13. The cooling air supply apparatus according to claim 10, wherein the
first operable closure element is operationally linked for emergency
operation and coupled with a load-limiting slip clutch to the actuator.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001]This application claims priority to German Patent Application No.
102009014003.4, filed Mar. 19, 2009, which is incorporated herein by
reference in its entirety.

TECHNICAL FIELD

[0002]The present invention relates to a cooling air supply apparatus for
the internal combustion engine of a motor vehicle, which is provided with
an emergency operation device for at least one of its closure elements.

BACKGROUND

[0003]The heat generated in operation of an internal combustion engine of
a motor vehicle is typically dissipated to the surroundings using a heat
exchanger which can have an air stream flow through it. Such heat
exchangers, which are commonly referred to as radiators, are designed so
that even at maximum power development of the engine, also under extreme
external conditions at external temperatures above approximately
40° C. and more, they provide sufficient cooling.

[0004]In the predominant number of motor vehicles, the radiator is
situated in front of the internal combustion engine viewed in the travel
direction, so that a part of the travel wind can be used directly as the
cooling air to be supplied.

[0005]The air supply to the radiator occurs via air inlet openings of a
radiator grille, which can have greatly varying embodiments as a
component of the vehicle front depending on the vehicle design.

[0006]In the meantime, so-called active cooling air supply apparatuses
have come into existence, which regulate the cooling air supply to the
radiator on demand. Thus, for example, DE 102 28 422 A1 discloses a
louver for closing openings having pivotable louver elements situated
parallel to one another. Depending on the position and orientation of the
louver elements, the cooling air supply to the heat exchanger, or to the
internal combustion engine, can be regulated according to the cooling
requirements. In addition, the flow-technology geometry of the vehicle
changes with the adjustment of the louver elements. In the event of a
closed radiator louver, the air resistance of the motor vehicle
decreases, which is accompanied by an advantageous reduction of the fuel
consumption.

[0007]An actuating drive driven by an electric motor is typically provided
for the pivotable operation of individual louver elements, which is
activated and regulated by the onboard electronics of the vehicle.

[0008]Because opening of the louver element or air supply lamellae is not
required for cooling under normal operating conditions, the lamellae are
predominantly located in their closed position, in order to reduce the
air resistance of the vehicle. However, closed lamellae prevent the
dissipation of heat in particular after the vehicle is shut down, so that
critical overheating of the engine can occur.

[0009]Opening of ventilation openings which is solely actuated by an
electric motor thus lacks in reliability. For example, if the power
supply for the actuating mechanism is interrupted or other malfunctions
of the vehicle electronics occur, opening of ventilation openings, which
is required after the motor vehicle has been shut down and left, cannot
be provided with sufficient reliability.

[0010]The present invention is thus based on at least one object of
providing an improved cooling air supply apparatus for an internal
combustion engine of a motor vehicle, which offers increased reliability
for the opening of ventilation openings. The cooling air supply apparatus
is also to be able to be actuated independently of the onboard
electronics of the motor vehicle and is to be used for avoiding critical
overheating of the internal combustion engine, in particular when the
engine is shut down and the vehicle electronics are inactive. In
addition, other objects, desirable features and characteristics will
become apparent from the subsequent summary and detailed description, and
the appended claims, taken in conjunction with the accompanying drawings
and this background.

SUMMARY

[0011]The at least one object, other objects, desirable features and
characteristics, on which the invention is based is achieved using a
device for emergency operation and a cooling air supply apparatus. The
device according to an embodiment of the invention is implemented for the
emergency operation of at least one closure element of a cooling air
supply apparatus, for an internal combustion engine of a motor vehicle.
The cooling air supply apparatus, which typically comprises a radiator
grille having a number of ventilation openings, has at least one closure
element provided for emergency operation, in particular for emergency
opening, which is mechanically operationally linked to an actuator of the
emergency operation device.

[0012]The closure element is situated so it is movable between a closed
position and an open position, it essentially closing a ventilation
opening in its closed position and it releasing this ventilation opening
for cooling air to flow through in the open position. The actuator which
is coupled to the closure element is implemented according to an
embodiment of the invention for the purpose of automatically transferring
the closure element into the open position if a predetermined temperature
is exceeded.

[0013]In this way, an adjustment movement for the closure element which is
triggered by the actuator and initiated there from can be provided
independently of the actual actuating drive of the closure element or the
closure elements. The actuator of the emergency operation device can be
implemented as completely autonomous and decoupled from the onboard
electronics of the motor vehicle and/or from the actuating drive of the
cooling air supply apparatus.

[0014]The actuator can additionally assume a double function, in that, on
the one hand, it detects the occurrence of a temperature lying above a
predetermined temperature level and, on the other hand, in direct
reaction thereto, it initiates a mechanical adjustment movement of the
closure element and generates and provides a force required for this
purpose or a corresponding adjustment torque.

[0015]According to a first advantageous embodiment of the invention, the
actuator is implemented as a temperature-sensitive element and is subject
to a length, shape, or size change as a function of the ambient
temperature. The temperature-related change of the geometry or the
external contour of the actuator is transferred into the required
adjustment movement for the closure element. The length, shape, or size
change of the actuator then initiates and causes the adjustment movement
of the closure element, in order to provide an emergency opening
mechanism for the cooling air supply apparatus.

[0016]According to an advantageous refinement of the invention, the
actuator is coupled to a restoring mechanism, which transfers the closure
element into the closed position in the event of a temperature drop below
a predetermined temperature level. The restoring mechanism can have a
restoring spring, for example, which counteracts an opening movement of
the closure element and which is designed to store a spring force upon
transfer of the closure element into its open position.

[0017]The actuator and the restoring mechanism are adapted to one another
in such a way that the force provided by the actuator in the event the
predetermined temperature is exceeded is greater than the restoring force
originating from the restoring mechanism.

[0018]According to a refinement of the invention, the closure element is
implemented as a lamella which is mounted so it is rotatable, without
restricting the invention thereto, however. Thus, for example, pivotable
or translationally displaceable or movable configurations of the closure
element are similarly conceivable.

[0019]According to a further advantageous embodiment of the invention, the
actuator and a lamella which is mounted so it is rotatable or pivotable
are connected to one another using a crank linked radially spaced apart
from the rotational axis of the lamella. In this way, a translational
movement which is generated by the actuator and originates there from can
be converted into a rotational movement of the lamella.

[0020]The radial spacing of the linkage point of the crank to the
rotational axis, or a crankshaft which is coincident with a rotational
axis of the lamella, determines the transmission ratio of a linear
movement originating from the actuator into a rotational movement of the
lamella.

[0021]According to a further advantageous embodiment of the invention, the
actuator is implemented as a bimetal spring. An actuator of this type is
subject to a change of its shaping in the event of temperature
variations. This temperature-induced shape change can be used according
to the invention for the adjustment movement of the closure element.

[0022]According to a further embodiment of the invention, the actuator has
a cylindrical receptacle for any medium which expands under the effect of
heat and a piston which is situated so it is movable in the receptacle.
This piston, which is situated so it is movable along the cylinder
longitudinal axis, can be regionally pressed out of the cylindrical
receptacle by heat-related expansion of the medium situated between
piston and cylinder floor. Materials having a particularly high thermal
expansion coefficient come into consideration as the heat-sensitive
medium.

[0023]Materials which are subject to a change of their aggregate state in
the range of the temperature provided for the emergency opening may also
be used. Furthermore, a so-called expanding material, such as a wax, can
be used as the thermal medium. Thus, an adjustment movement of the
actuator which is required for the operation of the closure element can
be generated by heat-related melting of the wax. Furthermore, it is
advantageous if the volume of the medium situated in the cylinder changes
suddenly when the predetermined temperature is exceeded and temperature
variations outside this predetermined temperature range result in a
comparatively slight volume change of the medium. Such a sudden change of
the volume can be achieved in particular in the event of an aggregate
state change of the medium, in particular from solid to liquid or from
liquid to gaseous.

[0024]According to a further embodiment of the invention, the actuator is
in thermal contact with the engine of the motor vehicle. Thus, for
example, the actuator can be situated directly on the engine and coupled
to the closure element to be actuated via a traction-compression means,
for example, in the form of a rod or an actuating pull.

[0025]Furthermore, the actuator can be situated inside a housing, which is
directly connected to the engine or is in thermal contact therewith while
situated thereon.

[0026]According to an alternative embodiment of the invention, the
actuator can be activated using an electrical auxiliary drive, which is
powered by a power supply decoupled from the motor vehicle electronics.
For example, an auxiliary battery, which is situated in the immediate
surroundings of the auxiliary drive, is associated with such an auxiliary
drive. Furthermore, this auxiliary battery and the auxiliary drive can be
situated in a common housing, optionally coupled to a temperature sensor,
in order to provide a structural module provided for the emergency
opening of a ventilation opening, which is decoupled from the remaining
motor vehicle electronics and the power supply thereof.

[0027]According to a further independent aspect, the invention relates to
a cooling air supply apparatus for the internal combustion engine of a
motor vehicle having a number of closure elements which can be actuated,
at least one of which is equipped with a previously described device for
emergency operation. The closure elements may be implemented as lamellae
which are situated parallel to one another and are mounted so they are
rotatable or pivotable, for example, and which regulate the cooling air
supply to the radiator lying behind them using an actuating drive
provided for this purpose, depending on the required cooling.

[0028]The closure elements are particularly coupled to a common actuating
drive for the alternate opening and closing of corresponding ventilation
openings.

[0029]The at least one closure element provided for the emergency
operation can be decoupled from the remaining closure elements, which are
operationally linked to the actual actuating drive. Therefore, this
closure element, which is provided with the emergency operation device,
exclusively opens upon occurrence of a critical heat development which is
above a predetermined temperature. In normal operation of the vehicle, it
remains in a closed state.

[0030]According to a refinement, the closure element which is
operationally linked to the device for emergency operation can also be
coupled via a load-limiting clutch, such as a slip clutch, to the
actuating drive of the remaining closure elements. In normal operation,
the closure element is particularly operated by the actuating drive, and
upon occurrence of a critical temperature, the adjustment movement of the
closure element is taken over by the emergency operation device and the
actuator thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031]The present invention will hereinafter be described in conjunction
with the following drawing figure, where:

[0032]FIG. 1 shows a perspective illustration in partial section of a
cooling air supply apparatus having an emergency operation device.

DETAILED DESCRIPTION

[0033]The following detailed description is merely exemplary in nature and
is not intended to limit application and uses. Furthermore, there is no
intention to be bound by any theory presented in the preceding background
or summary or the following detailed description.

[0034]The cooling air supply apparatus 10, which is shown in detail in
FIG. 1, has a frame-like support structure having an upper frame part 22,
a lower frame part 20, a centrally situated vertical web 18, and a
lateral frame part 24. The cooling air supply apparatus is typically
implemented as a radiator grille for a motor vehicle and has multiple
lamellar closure elements 12, 14, 16, which are situated parallel to one
another and extend between the web 18 and the side part 24.

[0035]The lamellae 12, 14, 16 are shown in their open position in FIG. 1.
A ventilation opening 11 which is delimited by the frame 20, 22, 24 can
be closed to reduce the air resistance of the motor vehicle by pivoting
or rotating individual or all lamellae 12, 14, 16 by approximately
90°.

[0036]The lamellae 12, 14, 16, which are mounted so they are rotatable,
are coupled to a an actuating drive (not shown explicitly), which
regulates the cooling air supply by rotating or pivoting the lamellae 12,
14, 16 in operation of the vehicle as a function of the cooling to be
provided, or the required heat dissipation.

[0037]In the present exemplary embodiment, solely the upper lamella 12 is
equipped with an emergency operation device 26, which, upon the
occurrence of an ambient or engine temperature lying above a
predetermined critical temperature, transfers at least the lamella 12
into its open position shown in FIG. 1 independently of the actual
actuating drive, so that in particular the thermal energy existing or
arising after the engine is shut down and the corresponding heated air
can escape from the engine compartment of the motor vehicle.

[0038]The emergency operation device 26 is situated in a housing 36, which
is partially shown in section in FIG. 1, directly adjoining the outer
side of the side part 24. The emergency operation device 26 has an
actuator 32 situated inside the housing 36, which is coupled via a crank
drive 28 to the rotational axis of the lamella 12. In a manner of
speaking, the rotational axis of the lamella 12 penetrates the side part
24 and is engaged with a crankshaft 34 there, so that a linear upward
movement of the actuator 32, or a piston situated so it is displaceable
therein, results in a rotational movement of the lamella 12. The
crankshaft 34 lying outside the support structure 18, 20, 22, 24 is
coincident with an axial extension of the rotational axis of the lamella
12.

[0039]In addition, a restoring spring 30 is provided, which is implemented
to counteract the extension movement of the actuator 32, which is
directed upward in FIG. 1.

[0040]The actuator 32 has a cylindrical receptacle, which is filled with a
thermal medium and in which a piston is additionally guided so it is
displaceable along the cylinder longitudinal axis. As soon as the medium,
which is preferably implemented as wax, is subject to a heat-related
volume enlargement, the piston is pushed upward out of the receptacle.
This displacement movement of the piston is converted via the crank drive
28 and the crankshaft 34 into a corresponding rotational movement of the
lamella to open the ventilation opening 11.

[0041]As soon as the temperature falls below a predetermined temperature
level again, for example, through thermal convection and through the
outflow of heated air, the piston moves back downward into the receptacle
again because of the temperature-related volume decrease of the thermal
medium. This reversing movement is supported by the spring element 30.

[0042]The cooling air supply apparatus and its emergency operation device
thus provide operation of a closure element of a ventilation opening
which is purely temperature-controlled and optionally reversible.

[0043]While at least one exemplary embodiment has been presented in the
foregoing summary and detailed description, it should be appreciated that
a vast number of variations exist. It should also be appreciated that the
exemplary embodiment or exemplary embodiments are only examples, and are
not intended to limit the scope, applicability, or configuration in any
way. Rather, the foregoing summary and detailed description will provide
those skilled in the art with a convenient road map for implementing an
exemplary embodiment, it being understood that various changes may be
made in the function and arrangement of elements described in an
exemplary embodiment without departing from the scope as set forth in the
appended claims and their legal equivalents.